Another oil rig exploded and burned in the Gulf of Mexico yesterday. All crew members were rescued, and there has not been a confirmed report of a spill, so far. (It took a few days for a spill to be confirmed in the case of Deepwater Horizon.) The company that owned the rig, Mariner Energy, and its parent company, Apache Energy, paid $745,000 in fines for safety violations in 2010 alone.

BP plans to remove the failed blowout preventer from its Deepwater Horizon well by Sunday. After that, it will begin a bottom kill to seal the well permanently. The federal government wants to use the blowout preventer as evidence in the criminal and civil cases against the company.

A fuel tanker ran aground in the Canadian Arctic in the Northwest Passage. So far no spill has been reported.

Environment and biodiversity

The fight over mountaintop removal mining is shifting as large banks seek to reduce their involvement with companies that practice it and activists take their fight to the court system. A key question is whether the US EPA will limit valley fills to protect water supplies.

A new study found that the oil sands project in Alberta is polluting local watersheds with toxic chemicals in levels that exceed Canadian safety standards. Chemicals are leeching from deforested sites around mines or falling as particulate air pollution. Heavy metals are known carcinogens in humans and also harm fish and aquatic wildlife.

A warming climate likely reduced the number of horseshoe crabs at the end of the last Ice Age. Future climate change could have a similar effect, leading to problems for other wildlife that depend on horseshoe crabs and their eggs for food.